The present invention relates to an adjustable seat support mechanism, such as for supporting a seat in an agricultural vehicle.
Off-highway vehicles, such as agricultural tractors, often operate over inclined or side hill terrain. In order to reduce operator fatigue, there have been proposed adjustable support mechanisms for automatically or manually leveling the operator's seat under such conditions. Certain of these mechanisms utilize track and roller bearing support members. However, the low friction of such supports can permit overly abrupt seat movements unless additional damping is provided, such as the fluid damping described in U.S. Pat. No. 3,632,076. Furthermore, such systems produce point loading of the members which bear against the roller bearings. Such point loading requires that the bearing surfaces be treated, such as by case hardening, in order to support such loads. Such point loading can also create undesirable stresses upon structural members when the seat is subjected to seat belt stress forces. Low friction bearing supports also have a certain amount of free play which can produce undesirable noise and vibration which reduces operator comfort.
Conventional seat leveling supports also provide latching mechanisms which releasably hold the seat in selected positions. However, some of these latching mechanisms are inconvenient to operate. For example, the latch mechanism of U.S. Pat. No. 3,466,089 requires the operator to grasp a dog which is mounted underneath the front part of the seat. Other latch mechanisms, such as those described in U.S. Pat. Nos. 937,922 and 1,039,004, have parts which extend outwardly from the seat and could interfere with the utilization of space within a vehicle operator's compartment. Accordingly, it would be desirable to provide a seat leveling mechanism which is rugged, noise and vibration resistant, which has a compact latching mechanism and which does not require hydraulic damping.